This is a classic article, widely read and often quoted. The existence of objective knowledge and the possibility of communicating it by means of language were rarely questioned by educators until 1970 when Kuhn's book, The Structure of Scientific Revolutions, was published. Since that time, work in the area of philosophy of science has suggested a different view of knowledge. In this article, von Glaserfeld presents an alternative theory of knowing that takes into account the thinking organism's cognitive isolation from "reality," and draws on the writings of Vico and Piaget, as well as Kuhn and others. Vico wrote in 1710 that individuals can know nothing but the cognitive structures they themselves have put together. This is a very different view of knowledge than commonly accepted (i.e., as a objective representation of an observer-independent world). von Glaserfeld posits that knowledge is the collection of conceptual structures that are viable within the knowing subject's range of experience. He goes on to elaborate on the role of social interaction and language in the "construction" of knowledge and understanding. The implication for education is that knowledge cannot be simply transferred from one individual to another by means of words.